Apple Tree Rootstock Named &#39;D2212&#39;

ABSTRACT

A new and distinct variety of apple tree rootstock that exhibits compatibility with all apple varieties and resistance to Candidatus Phytopiasma mali and Athelia rolfsii.

CROSS REFERENCE TO RELATED APPLICATION(S)

This application claims the benefit of priority from U.S. ProvisionalPatent Application No. 63/361,051, filed Nov. 18, 2021, which isincorporated herein by reference in its entirety.

Botanical classification: Malus mill.

Varietal denomination: ‘D2212’

BACKGROUND OF THE NEW PLANT

The present invention comprises a new and distinct variety of apple treethat is solely used as a rootstock and known by the varietal name‘D2212’. The new variety was developed by the breeder as part of aplanned breeding program in Ahrensburg, Germany. The purposes of thebreeding program were to obtain rootstocks with resistance to CandidatusPhytoplasma maii and with reduced plant vigor. ‘D2212’ is the result ofopen pollination of an unpatented variety of M. domestica x M. sieboldiinamed ‘Laxton's Superb’ (female parent). As a result, the exact maleparent is unknown. The new variety was selected and first asexuallyreproduced by in-vitro propagation in Stuttgart, Germany.

When compared to unpatented Malus mill. varieties referred to as PJ-P 21(APU 85) and M 25 (APU 29), ‘D2212’ has crenate leaf blade marginincisions, while the comparison varieties have serrate leaf blade marginincisions. Further, ‘D2212’ has weak pubescence on the lower side of itsleaf blades, while M 25 (APU 29) has strong pubescence on the lower sideof its leaf blades. Also, resistance to Candidatus Phytoplasma mali andAthelia rolfsii are distinguishing characteristics of the new varietyfrom other apple tree varieties known to the breeder.

The new variety has not been evaluated under all possible environmentalconditions. The phenotype may vary with variations in environmentwithout a change in the genotype of the plant. The new variety has beentrial and field tested and has been found to retain its distinctivecharacteristics and remain true to type through successive asexualpropagations.

DESCRIPTION OF THE DRAWINGS

The accompanying photographic drawings illustrate the new variety atwith the color being as nearly true as possible with color illustrationsof this type.

FIG. 1 illustrates multiple plants of the new variety at approximately 1year of age;

FIG. 2 illustrates multiple young plants of the new variety; and

FIG. 3 illustrates the new variety at 7 years of age with fruitsthereon.

DETAILED BOTANICAL DESCRIPTION

The following detailed description sets forth the characteristics of thenew variety at approximately 1 year of age and on a mother plant at 7years of age. The data which defines these characteristics werecollected as a result of asexual reproductions carried out inRheinstetten, Germany on potted plants under standard growing conditionsand taken under natural light. Where applicable, color descriptions areprovided using X11 Color Names and their corresponding HEX Color Codes,accessed in August of 2022 viahttps://www.farbtabelle.de/de/farbtabelle.htm.

ROOTSTOCK

-   Height: 150.0 cm.-   Thickness: 12.0 mm.-   Vigor: Medium.-   Tree habit: Upright and straight growth.-   Form: Spindle.-   Use: Solely as a rootstock.-   Multiplication ability:    -   -   Layering.—Not determined to date.        -   Hardwood cuttings.—Very difficult.        -   Softwood cuttings.—Possible, but with low yields.-   Pathogen resistance: Resistant to Candidatus Phytoplasma mali and    Athelia rolfsii.-   Pest resistance/susceptibility: Not observed to date.-   Rootstock performance:    -   -   Root sprouts (suckering).—None.        -   Anchorage.—Stable in the ground.        -   Compatibility.—Compatible with all varieties.        -   Vigor.—Medium to strong.-   Shoot:    -   -   Diameter.—Thick at midpoint.        -   Internode length.—Medium to long.        -   Texture.—Pubescence present on upper half of shoot.        -   Glossiness of bark.—Medium to strong.        -   Color.—Reddish brown on sunny side.        -   Growing tip color.—Reddish.-   Buds:    -   -   Position.—Adpressed relative to axis.        -   Size.—Medium.        -   Shape of tip.—Pointed.        -   Support size.—Small to medium.-   Lenticels:    -   -   Quantity.—Average.        -   Length.—Medium to long.        -   Shape.—Elliptic.-   Petiole:    -   -   Shape.—Straight.        -   Length.—2.0 cm; 3.5 length of blade to length of petiole            ratio.        -   Diameter.—0.15 cm.-   Leaves:    -   -   Arrangement.—Alternate, spiral.        -   Length.—From 6.5 to 7.0 cm.        -   Width.—From 5.0 to 6.0 cm.        -   Form.—Generally, elliptic-oval. Lower base leaves are often            triangular with basal lobes.        -   Profile.—Concave in cross section.        -   Apex.—Pointed.        -   Base.—Orbicular-obtuse.        -   Margin.—Double saw incisions present.        -   Texture.—Upper surface is smooth; lower surface has weak            pubescence present.        -   Color.—Young leaves have bronze anthocyanin coloration            present.        -   Venation.—Type: Pinnate, alternate. Color: Slightly reddish            with very weak to weak anthocyanin coloration present.-   Flower buds:    -   -   Pedicel.—Length: 4.5 cm. Diameter: 1.0 mm. Color: Tan4, HEX            #8b5a2b.        -   Bud.—Length: 1.0 cm. Width: 4.0 mm. Color: HotPink, HEX            #ff69b4.-   Flowers:    -   -   Bloom timing.—From April 23 to May 8 in Rheinstetten,            Germany.        -   Blooming period.—Two weeks.        -   Number of flowers per cluster.—4 to 6.        -   Fragrance.—Weakly sweet.        -   Petals.—Number: 5. Length: 2.5 cm. Width: 1.7 cm. Shape:            Orbicular. Margin: Entire. Texture: Smooth.        -   Color.—When opening: Upper surface: Pink1, HEX #eea9b8.            Lower surface: MistyRose, HEX #ffe4e1. Fully opened: Upper            surface: White, HEX #ffffff. Lower surface: LightPink1,            #ffaeb9.        -   Sepals.—Shape: Rhomboid. Margin: Entire. Texture: Smooth.            Length: 4.0 to 5.0 mm. Width: 1.0 mm. Color: Upper surface:            OliveDrab4, HEX #698b22. Lower surface: OliveDrab3, HEX            #9acd32.-   Reproductive organs:    -   -   Stamens.—Number (per flower): 12. Filament length: 3.0 mm.        -   Anthers.—Shape: Round. Length: 1.0 mm. Color: Gold3, HEX            #cdad00.        -   Pollen.—Color: Gold3, HEX #cdad00.        -   Pistils.—Length: 2.4 cm.        -   Style.—Length: 7.0 mm. Color: Cornsilk3, HEX #cdc8b1.        -   Stigma.—Shape: Round. Color: NavajoWhite3, HEX #cdb38b.-   Fruit: Not observed to date.

I claim:
 1. A new and distinct variety of apple tree rootstock plantnamed ‘D2212’, as is herein illustrated and described.